Table 1.

Summary of the nanomaterials used in emerging CTC detection platforms.

Type	Chemical modification	Detection mechanism	Advantages	Ref.
Gold nanoparticles	Polymeric coating or linkers combined with CTC targeting ligands	Photoacoustic imaging after in vivo injection	No blood sampling issue Biocompatibility Potential for laser ablation of CTCs	17, 18, 23, 24
	Raman reporter molecule or silver coating combined with CTC targeting ligands	Ultrasensitive surface-enhanced Raman scattering (SERS)	Probes for CTC confirmation and quantitative measurement Potential to combine with other CTC capture platform	27-31
Magnetic nanoparticles (MNPs)	Polymeric coating or linkers combined with CTC targeting ligands	Isolation of CTCs from the drawn blood specimens	Ability to separate CTCs using an external magnet Potential to combine with other quantitative probes or CTC capture platforms	1, 35, 38-43
Quantum dots (QDs)	Polymeric coating or linkers combined with QDs and CTC targeting ligands	Fluorescence-based identification	Stable fluorescence intensity Potential for surface marker-dependent separation	45, 46
Graphene/ graphene oxides (GO)	Adsorption of dye- labelled biomolecules via pi-pi stacking	Fluorescence quenching Electrochemical impedance spectroscopy and cyclic voltammetry	Increased surface area Excellent thermal, electric conductivity and its optical transmittance Strong mechanical strength	49-51
Dendrimers/ Stimuli- responsive polymers	Covalent conjugation or modification with CTC specific antibodies/ligands	Immunostaining confirmation after CTC capture on the platform	Increased surface area Potential for post-capture culturing Potential for surface marker-dependent separation High cell viability	54, 58, 59, 61-66